How is wet waste processed at the KCDC?

The garden city that’s on the fast track to become garbage city has finally started understanding the importance of composting and recycling. Karnataka Compost Development Corporation, dedicated to composting, has come back to the limelight, by accepting extra organic waste.

A Muniraj, Technical Head, Karnataka Compost Development Corporation, who has been serving the firm since 1976, explained the composting process followed at the KCDC.

The KCDC has two microbial compost processing units and 300 pits that generate 200 tons of manure per day. Composting here is done by two methods – aerobic and vermi-compost.

Aerobic composting

Aerobic compost involves formation of windrows, a pile of waste of about 6 feet hight. This windrow is mixed with old decomposed waste and is kept untouched for the first eight days. A cow dung slurry is sprayedover the windrow, to stop bad odour and breeding of insects like flies and mosquitoes.

Windrow is turned over again and again at least eight times in a span of 30 days, in order to provide it with oxygen and maintain heat and moisture. The decomposed waste is then taken to the microbial filtering machines usually termed as 60 mm (B) and 4 mm (A).

60 mm (B) means it produces B grade quality of manure, out of which 60 per cent is plastic waste while rest is taken to the A grade machine i.e. 4 mm, for further filtration where another 15 percent of the material is segregated as plastic waste. After this step, the manure produced is ready to be packed and transported to distant buyers across Karnataka, Andhra Pradesh, Tamilnadu.

Vermi-composting

Vermi-composting uses worms like Easinea Fida and Eudrillus. Semi-degraded waste is mixed with cow dung and dry grass which acts as food for the worms. Dry grass also helps generate heat in the pit while the moisture is maintained in the pit by timely placing a moistened gunny cloth as a covering.

The worms eat the organic matter in the compost and secrete their waste, which gets accumulated on topmost layer of the pit. Therefore it becomes easy to segregate manure from the rest of the waste.

The manure produced by vermi-composting is required to go through the same filtering machines as the aerobic method, to get the final good quality manure.

The failed attempts to produce fuel from waste

Recyclable waste like iron filling, sharp metal objects and rubber tyres are sold to recycling units. However dialogues are on between the KCDC and contractors to treat the plastic waste and convert it into fossil fuel.

Many contractors had come forward in the past but it was not easy to treat the pile of plastic that is produced at the KCDC, says Basavaiah C, ex- Managing Director (2000-2008).

During Basavaiah’s tenure, two government-approved contractors, K K Plastics and L K R Plastics, had stepped forward and even initiated the work to convert the plastic waste into fuel. “However none could survive for more than a month,” he said.

As a result, over 50,000 tons of plastic waste generated from B grade machine remain untouched for over two years.

Muniraj points at the huge mountains of plastic waste and says, “every time a pile of decomposed mixed garbage is put into a processing unit, 75 percent of the mixture gets segregated as plastic and kept aside.”

This explains the biggest hurdle in composting. It also gives the reason why civilians should segregate plastic as dry waste and the processing should be done separately.

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